What happened
On October 19, 2022, a THRUSH S2R-T660, registration EC-MXL, departed Doade Aerodrome (Lugo) at approximately 11:35 h for a positioning flight to Córdoba Airport. The flight was intended to be conducted under Visual Flight Rules (VFR).
Shortly after takeoff, the pilot radioed the Doade base to report that weather conditions were favorable for the intended route. However, approximately 30 minutes later, the pilot contacted the base via telephone to report that weather conditions had deteriorated, making it impossible to continue to Córdoba or the designated alternate airports of Salamanca and Valladolid. The pilot stated an intention to divert to León Airport.
Following this last contact, the aircraft was not heard from again. A search and rescue operation was initiated, but the aircraft was not located until October 21, 2022. The wreckage was found in a mountainous area of the Sierra Segundera, near the municipal district of Porto (Zamora), at an elevation of approximately 1,850 meters. The aircraft had struck the terrain while flying straight and level, with no evidence of evasive maneuvers. The impact resulted in the death of the pilot and the total destruction of the aircraft.
The investigation
The CIAIAC investigation focused on the flight planning process, the meteorological conditions, and the failure of the aircraft's Emergency Locator Transmitter (ELT) to alert rescuers.
Investigators examined the pilot's decision-making process regarding the flight's commencement. Although the pilot had initially intended to cancel the flight due to weather below minimums, a temporary improvement in visibility prompted a reconnaissance takeoff. The investigation also analyzed the wreckage to determine the flight path and the state of the ELT system upon impact. It was discovered that while the ELT activated upon impact, the physical deformation of the aircraft caused a loss of continuity between the beacon and the antenna, preventing a signal from reaching the Cospas-Sarsat system.
Findings
- The primary cause of the accident was inadequate flight planning, specifically an underestimation of weather forecasts that indicated a very low probability of maintaining VFR conditions.
- The ELT failed to transmit a signal to the Mission Control Centre, which delayed the location of the wreckage by several days.
- The aircraft's Illustrated Parts Catalogue (IPC) did not accurately reflect the actual layout of the ELT system.
- There was a lack of standardization in the installation of ELT components across different aircraft of the same model, with variations even found in recently manufactured units.
Safety action
Following the accident, the operator, Plysa, implemented a mandatory annual refresher course for all pilots, focusing on flight planning, meteorology, NOTAMs, and risk management.
The CIAIAC issued four safety recommendations:
- To EASA and the FAA: Improve the design of ELT systems to ensure better crashworthiness and minimize the risk of the system becoming non-operational during an impact.
- To Thrush Aircraft, INC: Update technical publications and manuals to accurately reflect the ELT installation and implement measures to standardize the layout of ELT components during production.